This is another thing that creates bad teachers; they're more worried about their jobs then disciplining the kids. I've been called to task for being as strict as I am and my response to the parents and administration is always the same. I tell them that I'll quit education long before I let some little monster screw up my classroom.
For example, I had a student pissed off at me because I kept kicking her out for not working. I pulled her aside in the hallway (in front of a security camera) to try and sort something out. She told me to phuck off so I shipped her to detention. She came back in the next day with her mother, claiming that I "grabbed her by the arm and yelled at her in the hallway". The pricipal and I pulled up the security tape and showed mom what really happened. I then told mom that she had better be ready with a lawyer if she came in and pulled that shit again because I'd sue her ass for threatening my career.